Alterations in the choroidal thickness and retinal vascular caliber in keratoconus.

PURPOSE: To compare the choroidal thickness (CT) and retinal vascular caliber in the differentiation of patients who have keratoconus (KC) from those of astigmatic and normal patients. METHODS: This was a prospective, cross-sectional study. A total of 72 patients who had KC, 70 who had astigmatism, and 83 healthy control subjects were enrolled in this study. All the patients were examined using the Sirius topography system and spectral domain optical coherence tomography with enhanced depth imaging. Using the digital fundus photographs, the retinal vascular calibers were calculated. The measurements were also analyzed between the KC stages according to the Amsler-Krumeich classification. RESULTS: The CT measurements were significantly higher in the KC group, when compared with the other 2 groups, in each location (P < 0.05). No statistically significant difference was observed with regards to the central retinal artery equivalent (CRAE) values (P = 0.959), while significant differences were noted in the central retinal vein equivalent (CRVE) among the groups (P = 0.011). Significant increases were noted in the CT as the stage of KC progressed, except at temporal 3000 µm (P = 0.603). No statistically significant difference was observed with regards to the CRAE among the stages (P = 0.901). However, the CRVE changes increased remarkably as the stages advanced (P < 0.001). CONCLUSION: The patients who had KC seemed to have a thicker CT and higher CRVE values than the healthy individuals, and these differences were progressively increased as the stages of KC advanced. Reflecting the vascular effects of inflammation, the high CRVE supported theories based on the inflammatory component of KC.

Evaluation of eye involvement in paediatric celiac disease patients.

BACKGROUND: The non-classic presentation of paediatric celiac disease (CeD) becomes increasingly common in daily practice, which requires an awareness of eye findings. The purpose of this study was to evaluate eye involvement and effect of gluten-free diet on ocular involvement in paediatric CeD patients by measuring the thicknesses of choroid and ganglion cell complex (GCC) composed of retinal nerve fibre layer, ganglion cell layer and inner plexiform layer using enhanced depth imaging optical coherence tomography. METHODS: Forty-three CeD patients aged between four and 16 years (mean age: 9.9 ± 4.1, 12 boys and 31 girls) and 48 healthy children (mean age: 11.3 ± 4.1,17 boys and 31 girls) were compared. Following comprehensive eye examinations, thicknesses of choroid at three points and GCC layers (retinal nerve fibre layer at five points, ganglion cell layer and inner plexiform layer) were obtained using enhanced depth imaging optical coherence tomography. Measurement of thicknesses of choroid and GCC layers by a trained optical coherence tomography technician and an ophthalmologist who were not aware about group of children in paediatric CeD patients with 1 year gluten-free diet was carried out. RESULTS: All layers of subfoveal, nasal and temporal choroid were significantly thinner in CeD than in the control group (P < .001, all, respectively). No significant difference was observed between the CeD and control groups in terms of GCC thicknesses (P > .05, all, respectively). CONCLUSION: Paediatric CeD caused thinning of subfoveal, nasal and temporal areas of choroid, and this change is apparent even after 1 year gluten-free diet. This eye involvement should be more closely screened at diagnosis, and long-term clinical results of thin choroid should be determined. Thicknesses of GCC layers were not different in CeD group and may reveal the effect of diet or not involvement.

Choroidal thickness in keratoconus.

PURPOSE: Keratoconus is an ectatic eye disease characterized by progressive thinning and steepening of the cornea which leads to irregular astigmatism and visual function loss. Determination of choroidal thickness in keratoconus patients may help us to better understand and manage the keratoconus disease. Choroidal thickness may be a potential marker for disease activity in keratoconus patients. In this study, we aimed to determine choroidal thickness in keratoconus patients and compare the results with the age-matched control group. METHODS: This is a prospective study with a control group. Keratometry and thinnest corneal thickness was measured and recorded in keratoconus patients. Choroidal thickness of all subjects was measured using an optical coherence tomography device (Spectralis OCT, version 6.0, Heidelberg Engineering, Germany) with an enhanced depth imaging mode without pupil dilation. Mean choroidal thickness of keratoconus patients was compared with healthy subjects. RESULTS: One hundred and sixty eyes of 80 healthy subjects and 160 eyes of 80 keratoconus patients were included in the study. Mean thinnest corneal thickness of the keratoconus patients was 449.7 ± 3.2 microns. Mean corneal keratometry value and cylindrical refraction error in the keratoconus patients were 53.2 ± 0.2 and 3.3 ± 0.1 diopters, respectively. Mean choroidal thickness was 363.9 ± 59.8 and 328.4 ± 67.2 microns in keratoconus patients and healthy subjects, respectively. There was a very significant difference between keratoconus patients and healthy subjects in terms of choroidal thickness (P = 0.000). There was not a statistically significant correlation between choroidal thickness and thinnest corneal thickness in keratoconus patients (P = 0.814). CONCLUSION: Choroidal thickness was found to be increased in keratoconus patients. Choroidal thickness could potentially become a new clinical marker for disease activity in keratoconus patients.

Comparison of optic coherence tomography results in patients with diagnosed epilepsy: Findings in favor of neurodegeneration.

BACKGROUND: Epilepsy is a chronic neurological disease characterized with recurrent seizures. Progressive neuronal degeneration is a common consequence of long-term and/or recurrent seizure activity in epilepsy. Optical coherence tomography (OCT) is a new medical imaging technique that displays biological tissue layers as high-resolution tomographic sections. The aim of our study was to evaluate OCT findings in patients with epilepsy and to compare OCT findings in terms of disease duration, presence of status, seizure frequency, and drug use. METHODS: Forty-three patients who had epilepsy according to the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE) in 2010 and 40 healthy controls were recruited for the study. Disease duration, seizure frequency, status history, and multiple drug use were noted. Retinal nerve fiber layer (RNLF), ganglion cell layer (GCL), inner-plexiform layer (IPL), and choroid thinning were analyzed by using spectral OCT. RESULTS: The mean RNFL values are 101.48 ±â€¯11.33 in the patient group and 108.76 ±â€¯8.37 in the control group (p = 0.001). The mean GCL thickness values in the patient and control groups are 1.14 ±â€¯0.12 and 1.22 ±â€¯0.05, (p < 0.001). The mean IPL thickness is 0.93 ±â€¯0.09 in the patient group and 0.97 ±â€¯0.05 in the control group (p = 0.02). Choroid thickness is significantly increased in the patient group (p < 0.001). CONCLUSIONS: Demonstration of RNFL, IPL, and GCL thinning might indicate neurodegeneration, and choroid thickening indicates neuroinflammation. We found no association between disease duration, seizure frequency, status history, and multiple drug use and OCT parameters. Further studies with larger patient groups should clarify the matter.

Comparison of nitric oxide level in Behçet's disease patients with or without psychiatric comorbidity.

Both Behçet's disease (BD) and major depressive disorder (MDD) are diseases associated with nitric oxide (NO). We hypothesized that the comorbidity of MDD affects the levels of NO in BD. In this study, we investigate whether there was a difference in NO levels among BD patients with accompanying MDD, BD patients with no depressive symptoms and healthy control group. There was a significant difference in NO levels among BD and control group (P < 0.05). Also, there was a significant difference between the BD group with MDD and BD group without psychiatric comorbidity in terms of NO levels (P < 0.05). This study is interesting as it demonstrates that accompanying psychiatric comorbidity puts an additional NO burden on the shoulders of BD patients.

Choroidal Thickness in Children with Beta Thalassemia Major.

PURPOSE: The purpose of this study was to determine whether there are differences in choroidal thickness in children with beta thalassemia major (ß-TM). METHODS: Thirty-five patients with ß-TM and 38 healthy children aged between 3 and 16 years participated in the study. After complete eye examinations were conducted on the participants, choroidal thickness measurements were performed using optical coherence tomography. Correlations between choroidal thickness and laboratory and clinical parameters, such as age, sex, hemoglobin and ferritin levels, duration of disease, type and duration of chelating therapy, visual acuity, intraocular pressure, central corneal thickness, and axial length were also evaluated. RESULTS: The mean ages for the study group and for the control group were 8.2 ± 2.7 and 7.9 ± 2.4 years, respectively. There were no statistical differences between groups in terms of visual acuity, intraocular pressure, central corneal thickness, or axial length (p > 0.05). Choroidal thicknesses at the foveal center were 286 ± 33 µm in ß-TM patients and 335 ± 423 µm in the healthy control children. Choroidal thicknesses at each point within the horizontal nasal and temporal quadrants were thinner in the ß-TM group. There was a positive correlation between choroidal thickness and hemoglobin levels and a negative correlation between choroidal thickness and ferritin levels (r = 0.924, p < 0.001 and r = -0.947, p < 0.001, respectively). There was no correlation between clinical or ocular characteristics and choroidal thickness. CONCLUSIONS: Choroidal thickness was significantly thinner in all quadrants in children with ß-TM. This thinning of the choroid may be the reason for the development of eye disorders in older patients with ß-TM.

Simultaneous Bilateral Endonasal Endoscopic Dacryocystorhinostomy: A Low Cost, Fast, and Successful Method.

The etiology of primary nasolacrimal duct obstruction is largely unknown, and this disease may occur bilaterally in a small percentage of patients. In this retrospective study, the authors aimed to discuss the cost, operation time, complications, and success rate of simultaneous bilateral endonasal endoscopic surgery. Twenty-eight patients (16 female, 12 male) were enrolled in this study, with a mean age of 55 years old (range: 43-76). The success rate was 91% (51/56), and the mean operation time was 44 minutes. Only minor and transient complications were observed in 2 of the patients. Overall, the authors believe that a bilateral endoscopic dacryocystorhinostomy would be useful in a single session, based on its advantages of low morbidity, low cost, and high success.

Reduction in Retinal Ganglion Cell Layer, Inner Plexiform Layer, and Choroidal Thickness in Children With Autism Spectrum Disorder.

PURPOSES: The aim of this study was to evaluate the retinal nerve fiber layer (RNFL), choroidal layer, inner plexiform layer (IPL), and ganglion cell layer (GCL) in patients with autism spectrum disorder (ASD). METHODS: In this study, we measured the thickness of the RNFL, GCL, IPL, and choroidal thickness using a spectral optical coherence tomography (OCT) device and we compared the results between the children diagnosed with ASD and healthy controls. Correlation between the Childhood Autism Rating Scale (CARS) and the OCT data was evaluated. RESULTS: Both ASD and control group consisted of 40 subjects (30 males and 10 females). Of the children in the ASD group, 29 had normal intelligence and 11 had mild intellectual disability (MID). The mean age of patients in the ASD group and control groups were 9.77 ± 3.37 years and 9.85 ± 3.97 years (p = 0.928). There was a statistically significant difference between the ASD group and the control group in the nasal and nasal-superior sectors of the RNFL layers in the left eye when all the lower layers of RNFL were assessed. In both eyes, the children with ASD had considerably lower mean choroidal thicknesses than the controls. When compared to the controls, the GCL and IPL volumes in the individuals with ASD were considerably lower in both eyes. Compared to the MID group, the left GCL volume of the nasal-inferior group was noticeably higher. A significant correlation was found between CARS scores and left GCL left IPL. CONCLUSIONS: In contrast to RNFL in the ASD group, significant reductions in IPL, GCL, and choroidal thickness were observed in both eyes. It is thought that GCL may be a much more important biomarker than RNFL in terms of representing the structural deterioration in the brain. In addition, these results may form the basis for a new perspective on the use of OCT for the diagnosis and clinical course of autism.

The Effect of Topical 0.05% Cyclosporine in the Prevention of Recurrence Following Pterygium Surgery.

OBJECTIVES: To evaluate the effect of topical cyclosporine A (CsA) (Restasis, Abbvie, Lake Bluff, IL, USA) on recurrence rates and tear metrics after pterygium excision and limbal-conjunctival autografting (LCUA) technique in patients with primary pterygium. METHODS: A total of 60 eyes of 60 patients with primary pterygium who underwent pterygium excision and the LCUA technique were evaluated prospectively. Among them, 30 eyes of 30 patients were treated with topical CsA (Restasis) for 6 months postoperatively (Group 1). The remainder of the patients were assigned to Group 2. The follow-up period was 12 months for each group. The primary outcome measures were a comparison of Schirmer I test and fluorescein tear break-up time (FTBUT) results, the recurrence rate, and postoperative complications. RESULTS: There were no significant differences in age (mean age of Group 1 and 2 was 55.0±9.7 years and 56.3±8.9 years, respectively) or sex between groups (p>0.05). Farmers were the largest group of patients (40.0%). Recurrence of pterygium was observed in 5 (16.6%) eyes in Group 1 and 8 (26.6%) eyes in Group 2. The recurrence rate was not statistically significant between groups (p=0.35). The complication rate was significantly lower in Group 1 compared with that of Group 2 (p=0.02). The average increase in Schirmer I and FTBUT values was significantly higher in Group 1 than in Group 2 (p<0.05). CONCLUSION: The use of topical CsA did not demonstrate any significant improvement in the recurrence rate of pterygium following LCUA surgery.

Assessing the role of systemic inflammation in the etiopathogenesis of advanced stage keratoconus.

PURPOSE: It was aimed to compare the levels of inflammation-related parameters, such as neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR), in patients with advanced keratoconus (KC) and healthy controls. Also, we evaluated the relationships between these parameters and several corneal topography values used in the KC diagnostic index. METHODS: Forty patients with advanced and 40 healthy volunteers were included in this study. In the KC group, 20 patients were nonprogressive KC and 20 patients were progressive KC. In all participating individuals, we evaluated detailed ophthalmologic examination findings and complete blood count data, while corneal topographic measurements were also recorded in patients with KC. RESULTS: The mean NLR value was 2.3 ± 1.19 in the progressive KC group; nonprogressive KC values were 1.99 ± 1.69 and 1.81 ± 0.72 in the control group. Mean PLR value was 113.24 ± 48.44 in the progressive KC group, nonprogressive KC values were 96.47 ± 31.04 and 104.09 ± 35.14 in the control group. No statistically significant difference was found between patients with progressive KC, nonprogressive KC, and healthy volunteers in terms of mean NLR and PLR values (P > 0.05). NLR values were found to demonstrate significant positive correlations with the corneal topography parameters, Symmetry Index front (r = 0.278, P = 0.025), KC Vertex front (r = 0.247, P = 0.048), and Baiocchi Calossi Versaci front (r = 0.273, P = 0.028); there was no significant relationship between corneal topography parameters and PLR values. CONCLUSION: Although there was no significant difference between the progressive KC, nonprogressive KC, and control groups in inflammation parameters such as NLR and PLR, a positive correlation was observed between the NLR value and some corneal topography findings used in the diagnosis of KC. The role of inflammation in the etiology of KC can be better understood by clinical studies and laboratory tests conducted with prospective studies involving a higher number of patients.

Comparison of the Retinal and Choroidal Structures in 3 Refractive Groups.

OBJECTIVES: This study investigated the retinal layer thickness, choroidal thickness (CT), and retinal nerve fiber layer (RNFL) parameters in 3 refractive groups. METHODS: A total of 201 eyes of 201 subjects were enrolled in this prospective and comparative study. The patients were divided into 3 groups according to refractive status: Group 1 consisted of 60 eyes of myopic subjects, Group 2 comprised 72 eyes of emmetropic subjects, and 69 eyes of hyperopic subjects were categorized as Group 3. The retinal layer thickness, CT, and RNFL parameters were measured using optical coherence tomography and compared between groups. RESULTS: The mean age of the patients was 22.33±10.11 years in Group 1, 21.55±8.3 years in Group 2, and 23.73±11.08 years in Group 3 (p=0.741). Group 1 consisted of 34 women and 26 men, Group 2 contained 44 women and 28 men, and Group 3 was made up of 45 women and 24 men (p=0.124). The mean spherical equivalent value was -6.16±2.01 D in Group 1, 0.13±0.5 D in Group 2, and 5.48±1.32 D in Group 3 (p<0.001). The RNFL and macular thickness values were lower in the myopic patients compared with those of the other groups (p<0.05). The CT measurement was lower in the myopic patients and higher in the hyperopic patients compared with the emmetropic patients (p<0.05). CONCLUSION: The myopic patients had a lower CT and RNFL thickness measurement than the emmetropic and hyperopic patients, whereas the hyperopic patients had a higher CT than the other patient types.

Long-Term Substance Use Can Cause Irreversible Photopic Vision Changes in Substance Use Disorder in Remission.

OBJECTIVE: Substance use has such effects on pupil diameter. Although there is knowledge about the acute effects of substances on pupils, studies showing their chronic effects are limited. The aim of the present study was to evaluate the effect of long-term substance use on scotopic, mesopic, and photopic vision. METHODS: The present study with cross-sectional desgn was conducted at the Adiyaman Training and Research Hospital for Psychiatry in Adiyaman. This study involved 110 substance use disorder (SUD) patients and 46 healthy volunteers as the control. The parameters were measured and recorded automatically by a device. RESULTS: The mean age was 23.44±5.53 years in the SUD group and 24.26±5.38 years in healthy controls (p=0.420). The mean age of onset of the substance was 17.74±3.89 years and the mean duration of substance use was 3.54±2.9 years. It was determined that the patients had not used any substance for a mean of 121.73±117.49 days. There was no significant difference between patient and control groups in terms of scotopic and mesopic measurements of both eyes (p>0.05). Photopic measurements were significantly higher in the patient group than in the control group (p<0.05). Photopic measurements were significantly higher in the opioid, cannabis, ecstasy, and multiple substance use groups than in the control group (p<0.05). CONCLUSION: The most important topic of this study is that photopic vision is permanently impaired in patients with a history of chronic substance use. This was attributed to disrupted sympathetic-parasympathetic hierarchy.

Investigation of neurodegenerative and inflammatory processes in sleep bruxism.

Objective: The present study aimed to evaluate the anxiety and optical coherence tomography (OCT) findings in patients with sleep bruxism (SB) and to develop objective measurements to assess the neurodegenerative and inflammatory processes associated with this disease. Methods: A group of 40 SB patients were compared with a control group consisting of 40 healthy individuals (without SB). Anxiety results and the OCT measurements of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and choroidal thickness were assessed in both groups. Results: Anxiety values in the bruxism group were significantly higher than those in the control group. The measurements of RNFL, IPL, and GCL in the bruxism group were significantly lower than the control group, whereas the choroidal thickness was significantly higher. Conclusion: According to literature, this is the first study that analyzed the changes in the retinal structures in bruxism, which revealed that SB is a neurodegenerative and inflammatory process.

Increases in retinal nerve fiber layer thickness may represent the neuroprotective effect of cannabis: an optical coherence tomography study.

Although optical coherence tomography (OCT) has been used in many neuropsychiatric disorders, data on substance use disorders (SUD) are not available. The aim of this study was to evaluate ganglion cell layer (GCL), inner plexiform layer (IPL), retinal nerve fiber layer (RNFL), and choroidal layer thickness in patients diagnosed with SUD especially cannabis use disorder (CUD). RNFL, GCL, IPL, and the choroidal layers of 111 patients diagnosed with SUD and 45 healthy controls were retrospectively analyzed. Fifty patients were diagnosed with CUD and 50 patients had multiple drug use (MDU). The mean age of the patient and control groups were 23.39 ± 5.53 and 28.48 ± 5.21 years, respectively. The mean duration of substance use was 3.53 ± 2.95 years. The patients had not used any substance for a mean of 121.45 ± 116.99 days. When the RNFL values of the SUD, MDU, and control groups were compared, no significant difference was found except for such components. However, there were significant differences in terms of right naso-superior (p = 0.020), right temporo-inferior (p = 0.024), right temporo-superior (p = 0.002), left naso-superior (p = 0.005), left naso-inferior (p = 0.043), and left temporo-superior (p = 0.008) between CUD and control groups. That is, RNFL values were higher in the CUD group than in the control group. Cannabis has medical uses because of its possible neuroprotective properties. Our study supports the possible neuroprotective effects associated with cannabis through RNFL data. According to our best knowledge, this is the first study investigating the association between RNFL and drugs, particularly cannabis.

Investigation of the effects of temporomandibular joint arthrocentesis on blood volume of the retinal structures.

OBJECTIVE: Arthrocentesis is a minimally invasive surgical procedure that is used to alleviate the symptoms of temporomandibular joint (TMJ) disorders. The aim of this study was to investigate the effect of arthrocentesis on the blood supply to the retinal structures. MATERIALS AND METHODS: Arthrocentesis was performed on 20 patients with TMJ disorders, and choroidal thickness (CT) in patients was measured to evaluate retinal blood circulation. The blood volume of the retinal structures was evaluated ipsilaterally before and after arthrocentesis, and these measurements were then compared with measurements obtained from the contralateral side. RESULTS: Before arthrocentesis, there were no differences in retinal blood volumes between the ipsilateral and contralateral sides (P = 0.96). When ipsilateral CT measurements taken before and after arthrocentesis were compared, retinal blood supply was found to have significantly decreased after arthrocentesis (P = 0.04). When contralateral CT measurements taken before and after arthrocentesis were compared, retinal blood supply was also found to have decreased after arthrocentesis, but not significantly (P = 0.19). CONCLUSION: The solution of local anesthesia with epinephrine applied before the arthrocentesis procedure was found to reduce the blood volume of the retinal structures. To the best of our knowledge, this is the first study that has investigated the blood volume of the retinal structures following arthrocentesis.

Evaluation of choroidal perfusion changes in obese patients: ocular effects of insulin resistance.

PURPOSE: We aimed to evaluate choroidal per-fusion changes in obese patients using optical coherence tomography and dynamic contour tonometry, to determine whether these changes are associated with body mass index, and to assess the ocular effects of insulin resistance. METHODS: We retrospectively evaluated the data of 32 obese patients with body mass index >30 kg/m2 and 45 healthy control individuals. Intraocular pressure and ocular pulse amplitude values of the patients were measured using dynamic contour tonometry, and the mean choroidal thickness was measured using enhanced depth imaging optical coherence tomography. Insulin resistance was assessed using the homeostasis model assessment-estimated insulin resistance index. RESULTS: The mean choroidal thickness (294.30 ± 60.87 µm) and ocular pulse amplitude (2.10 ± 0.74) were lower, whereas the mean intraocular pressure (16.61 ± 2.35 mmHg) was higher in obese patients than in controls. There was a significant negative correlation between body mass index and ocular pulse amplitude (r=-0.274; p=0.029) and an insignificant negative correlation between mean choroidal thickness, intraocular pressure, and body mass index. There was an insignificant negative correlation between homeostasis model assessment-estimated insulin resistance index, mean choroidal thickness, and intraocular pressure and significant ne-gative correlation between homeostasis model assessment-estimated insulin resistance index and ocular pulse amplitude (r=-0.317; p=0.022). CONCLUSION: We found reduced mean choroidal thickness and ocular pulse amplitude and increased mean intraocular pressure in obese patients. These changes indicated a decrease in choroidal perfusion and ocular blood flow. It may be possible to detect ocular blood flow changes in obese patients through noninvasive assessment using the choroid. The negative correlation between insulin resistance and ocular pulse amplitude may be associated with intracellular fat accumulation in obese patients.

Effects of combined oral doxycycline and topical cyclosporine treatment on ocular signs, symptoms, and tear film parameters in rosacea patients.

PURPOSE: This study reports the effects of combined use of oral doxycycline and topical cyclosporine on ocular signs, symptoms, and tear film parameters in rosacea patients. METHODS: Fifty-four right eyes of 54 patients were included in this study. All patients underwent full ophthalmologic examination-including best corrected visual acuity measurement, slit-lamp anterior segment and fundus examination, tear film break-up time, and Schirmer test-before treatment and six months post-treatment. Patients were divided into two treatment groups. The first group was treated with oral doxycycline 100 mg twice daily for the first month and once daily for the following two months. The second group received topical 0.05% cyclosporine emulsion drops twice daily for six months in addition to the oral doxycycline treatment regimen. All patients received preservati ve-free artificial tear drops, warm compress, eyelash cleaning, and topical corticosteroid drops three times daily for one month. RESULTS: A significant improvement in ocular signs and symptoms was recorded for all patients in groups 1 and 2 after treatment. There was not a significant difference in terms of itching, burning, meibomian gland inspissation, corneal neovascularization, and conjunctival hyperemia score changes between groups 1 and 2. The increases in Schirmer test and break-up time scores were significantly higher in group 2 than in group 1. CONCLUSIONS: Our results support the finding that topical cyclosporine in addition to the standard regimen improves tear function, as shown by Schirmer test and break-up time scores, in ocular rosacea patients.

Evaluation of thickness of retinal nerve fiber layer, ganglion cell layer, and choroidal thickness in essential tremor: can eyes be a clue for neurodegeneration?

The pathology of essential tremor (ET) and underlying mechanisms of the disease are still unclear, but an increasing amount of research has been conducted on the subject. Discussions are ongoing about ET's definition as a neurodegenerative disease. Optic coherence tomography (OCT) provides a window to the brain where direct visualization of central nervous system (CNS) changes may be possible, and it can help us to develop a new point of view on ET. The goal of this study was to examine OCT parameters in ET. 40 ET patients and 40 healthy controls, i.e., a total of 160 eyes were evaluated. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and choroid thinning were analyzed using spectral domain OCT. The mean age was 25.77 ± 8.98 in the ET group and 27.25 ± 8.22 in the control group. We found a decreased global RNFL thickness for both eyes in ET patients. All GCL and IPL thickness parameters were lower in the patients with ET (P < 0.001, P 0.03). Choroid was significantly thicker in ET patients than the controls (P < 0.001). Our study's results suggest that the usefulness of OCT in detecting neurodegeneration in ET. RNFL, GCL, IPL measurements are highly reproduced findings of neurodegeneration. Increased choroid volume may indicate neuroinflammation. Eyes in ET may shed light on nature of the disease, and may be used as a diagnostic tool.

Evaluation of retinal nerve fibre layer, ganglion cell layer and choroidal thickness with optical coherence tomography in migraine patients: a case-control study.

BACKGROUND: Evaluation of retinal nerve fibre layer (RNFL), ganglion cell layer (GCL) and choroidal thickness (CT) with optical coherence tomography (OCT) in chronic migraine patients, to compare with healthy controls. MATERIAL AND METHOD: Ninety-four eyes of 47 chronic migraine patients (Group 1) and 68 eyes of 34 healthy individuals (Group 2) were included in this prospective case-control study. The right and left eyes were separately evaluated. Mean peripapillary RNFL thicknesses, mean GCL measured from superior and inferior quadrants, and mean CT were measured at three different regions (central, 500 µm nasal and temporal region of the fovea). RESULTS: There was no statistically significant differences in RNFL between the two groups (p > 0.05), while CT values were significantly higher and GCL values were significantly lower in chronic migraine groups (p < 0.05). There were no statistically significant differences between migraine duration, frequency and length of attacks, presence of aura, relation to menstrual cycle, white matter lesions in cranial magnetic resonance imaging and RNFL, GCL and CT (p > 0.05). DISCUSSION: In this study, we observed chronic migraine disease does not have any effect on peripapillary RNFL thickness; however, increases in CT and decreases in GCL thickness were observed in migraine patients.